Since you're getting a Z87 motherboard, you might want to choose the i5 4670K. You can effortlessly overclock it to 4000mhz (just change a single number in the BIOS, save and exit, BAM free performance. Although, you might be limited by the heatsink if you stick with the default Intel one. The Hyper 212 EVO is an inexpensive but very quiet and efficient cooler, I suggest you use that if you go for overclocking.

You might find 120GB to not be a lot of space, so you might want to add a hard drive at some point. The good news are that you can do so whenever you actually need it, it's very easy to add a hard drive to an existing system.

While they do go over your budget and the latter is especially rather luxury, I always feel it's easier to compromise than settle for a low score to being with. The general idea of quality parts is there.

Not worth it at all, I've just been putting together my own new Intel Haswell based build which is much better than that and is coming out at around the same price.

There is absolutely no need for you to be getting a Core i7 CPU for what you want, let alone an enthusiast model; an i5 will more than suffice. For gaming put your money into your graphics card, not your CPU. Similarly there is absolutely no need to be going for an enthusiast level X79 chipset / 2011 socket based board. If you're willing to spend that kind of money, why build a new system based around Intel's Sandybridge architecture, why not go for Haswell instead? Go for an H87/Z87 socket 1150 based board, either an ATX or mATX form factor (you've no real need I suspect for ATX, there's less mATX around simply because ATX has been the general standard for a long time, but mATX is becoming more popular, there are good ones out there, and you'll save some money to put towards other components). I suggest an ASUS Z87M-PLUS or perhaps GRYPHON Z87, both mATX boards, and an i5 4570 or 4670.

You have no need for 16GB or RAM, 8GB would more than suffice.

Your graphics card is terrible. nVidia cards with x10 x20 (e.g. your 620) and x30 are low end cards, x40 and x50 are performance level cards, and x60 x70 x80 and x90 are entusiast level cards. For a decent gaming experience you'll probably want at least an x60, but it depends on what you mean and expect when you say gaming...

You have absolutely no need for a sound card, the capabilities built into the motherboard are more than perfect for almost anyone.

Do you really need wifi? Really really? Why not just use the wired ethernet port on the motherboard?

You've got a Corsair PSU, but what series? There are a few different series ranging from cheap "system builder" ones to professional highly-efficient ones. I'd recommend one from the TX series, perhaps HX if you want to throw down a little extra. If you're going to get a better graphics card, you'll likely want to move up to 650W or perhaps 750W.

You might like to get an SSD type hard drive for the Windows OS to be installed on, a 64GB or maybe 128GB model will do, no need to waste loads of cash on a larger one. Do get a large standard HDD in addition though for general storage and also for the installation of games (some games can require large chunks of disk space in the region of say 20GB each and the expense of getting a large SSD to cover that isn't worth it - note, when installing games you need to specify the folder/directory path it installs to, something sometimes hidden away in an 'advanced' mode in the installer, in order to get it to install on the other drive not the C: (OS) drive).

Since you're getting a Z87 motherboard, you might want to choose the i5 4670K. You can effortlessly overclock it to 4000mhz (just change a single number in the BIOS, save and exit, BAM free performance. Although, you might be limited by the heatsink if you stick with the default Intel one. The Hyper 212 EVO is an inexpensive but very quiet and efficient cooler, I suggest you use that if you go for overclocking.

You might find 120GB to not be a lot of space, so you might want to add a hard drive at some point. The good news are that you can do so whenever you actually need it, it's very easy to add a hard drive to an existing system.

* Corsair Dominator 2400MHz? It might make sense in AMD APU build or in general "all you can eat" build, but in this one they're and cost you an arm and a leg.

Recommend simple 1600MHz 2x4GB kit of whatever make and model. For example, Corsair XMS3 1600MHz would be a fine choice and for nearly 50 quid less.

* If you decide to go for an aftermarket heatsink, you might have to change from bog standard case to some more. For example, Hyper 212 will not fit into anything less than 195 - 200mm wide. Well, ComputerPlanet already tells you so (which is awesome - first online picker I'm seeing that does this). Hyper T4 will fit easily in 180mm, however.

With that in mind, I'd probably go for Cooler Master K280. It looks a bit aggressive, but it's surprisingly easy to hide cables in its extruded side panel - it's a rarity in this price range.

* Power supply is probably the most important part in your system. All sorts of problems might be directly or indirectly caused by a substandard power unit.

Corsair doesn't make them very bad, but VS series is extremely unwiedly still. I wonder why there aren't any options, but I'd much prefer OCZ ZT, for example.

* Recommend staying with simple internal card reader. If I recognize it correctly, Raidsonic IcyBox creates a massive clusterfsck in your case - it has six damn fat wires.

Now, pretty much any modern PC case has its own audio output and mic in - I fail to understand why they even put it there. Next - two USB 3.0 wires, one for each port, actually go through the case and out the back to the rear ports rather than the internal header. Again - clusterfsck and questionable design practices. And then eSATA, which I doubt anyone ever uses at all.

If you go for Cooler Master K280, it already has one USB 3.0 front port, too.

Apologies for not getting back to you earlier as was promised. I wasn't even doing my usual commentard service today.